anna coinman is live in our new york city newsroom. what reason does mayor bloomberg give for the drop in murders. >> mayor michael bloomberg says the decrease in crime is because of the city's commitment to end gun violence and new and improved police initiatives championed by police chief ray kelly. operation impact. it allows the nypd to track crime and set up more patrols where police can pa will control. >> essence of civilization is you can walk down your street without having to look over your shoulder. while clearly there is going to be bad apples in this city most apples are awfully good and we have reason to be happy with the performance. >> while though guns remain the leading cause of murder, commissioner kelly says they're preventing crime before they happen by taking st. critics argue though the numbers don't tell a proper story after violent crimes made headlines like a nanny killing two young children, two subway riders being pushed on to the track and a shooter opening fire at the empire state building. harris, this sa